1. Field of the Invention
The innovation concerns the field of harvesting of small fruit such as, for example olives, almonds, nuts, hazelnuts, chestnuts, cherries, mirabelles, plums, coffee-shrub berries, etc. . . . More precisely, it concerns the collection of small fruit which are detached from fruit trees or bushes by means of portable equipment (combs) or mechanized shakers, or by automated equipment, and are collected on a tarpaulin placed below the fruit-bearing branches of said trees or bushes and above the ground so that they will then be gathered and collected by using the roll-up action of said tarpaulin.
The present invention thus concerns a device for automatically extending a tarpaulin below the fruit-bearing branches, then to accompany its retraction in order to collect the fruit detached from the tree and fallen on said tarpaulin. It also relates to the process of deployment and retraction of such a tarpaulin. On the other hand, it applies to the self-propelled or drawn machinery equipped with such devices.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
For a long time tarpaulins or nets have been placed manually on the ground below fruit trees to be harvested, and to make the small fruit fall on said tarpaulins, for example by means of shakers or vibrations applied by some portable equipment or vibrators mounted on towed or self-propelled vehicles, and then to harvest the small fruit detached from the trees by gathering them while the tarpaulin is being rolled up. However, placement of the tarpaulin and its retraction require the presence of at least two workers and a considerable amount of time for installing and retracting the latter below the tree. This manual operation also cannot be carried out at night, as the manipulations and the environment present dangerous obstacles for operators working in the dark.
Document FR-A-2597704 describes a fruit harvesting machine which includes a receiving installation of fruit detached from the trees, built in two parts, each equipped with a receptacle provided, laterally, with a soft, deployable tarpaulin, and capable of being connected, in an articulated manner, one behind the other, the front part of said installation being built so it can be installed on the side of a farm tractor, whereas the rear part is built so it can be attached, in an articulated manner, to an element of the chassis of said front part. The distal edge of the tarpaulins is provided with handles so they can be unfurled and manually deployed under the tree to be harvested.
This machine which requires two separate attaching systems and two motorized devices for rolling up tarpaulins is fairly complex and costly; it is relatively space-consuming; it requires manual interventions for deployment and positioning the tarpaulins and several workers, but in spite of their presence the harvest can only proceed at a slow pace that is incompatible with the harvesting work in large olive groves or orchards.
Document FR-2556924 describes a device for handling and moving tarpaulins for the harvesting of fruit, intended to reduce the disadvantages of the system disclosed in the preceding document. This involves a tractor-drawn trailer on which a fruit-collecting tarpaulin is rolled up, said tarpaulin being deployed automatically below the trees. In order to avoid the disadvantages of a manual deployment/retraction of this tarpaulin, it is proposed to perform the deployment operations of the tarpaulin by pulling it by means of motorized trucks with driven wheels, each truck being equipped with a hydraulic motor, the whole being controlled from a tractor by a single person.
These trucks are however space-consuming, relatively slow to be moved during the deployment and retraction phases of the tarpaulin and require a complex mechanical platform to transport them on the trailer when the latter is moved from one tree to the next or on the roadway.
Furthermore, their control and their synchronization require the retraction and deployment of hydraulic hoses for the control of their motor which are subject to aggressive friction on the ground when the tarpaulin is deployed or retracted, reducing their useful life under these operating conditions. It is also often the case that machines perform the mechanical picking of the fruit, consisting of self-driven equipment which may, if necessary, need to roll on the surface of the tarpaulin and thereby damage the hydraulic control hoses of the trucks. The bursting of one or several of these hoses, apart from the fact that this prevents further utilization of the tarpaulin, is harmful to the environment due to the spillage of hydraulic fluid under pressure.
Finally, this system functions all right on a flat and even terrain, but it is very difficult to maintain a straight trajectory of the trucks on a sloping or hilly terrain without human intervention to correct it. Their trajectory for the deployment and retraction of the tarpaulin depends also on the terrain they encounter, as the terrain can very often be different for each of the drive trucks, thus causing their trajectory effectively to become random and resulting in the duration of overall operations of retraction and deployment to be long and unpredictable, depending on the terrain.
Document FR-2946832 proposes another system for the deployment of a small-fruit gathering tarpaulin by integrating inflatable tubes into it, thus ensuring a simple and rapid deployment of the latter, regardless of the conditions of the terrain. Such a system has however the disadvantage of being fragile, particularly if a harvesting machine needs to run on said tarpaulin, thus risking to pierce the tube and consequently rendering the tarpaulin effectively unusable because it can be neither deployed nor retracted, it also requires considerable volumes of compressed air to ensure the rapid deployment of the tarpaulin, adding to the complexity of the whole system by bringing in fuel-guzzling compressors and bulky fuel tanks. Finally, the replacement of the tarpaulin requires effectively the replacement of the tubes integrated into it, making maintenance operations of said tarpaulin more expensive.
Document EP-0133334 proposes a retraction and deployment system of a small-fruit gathering tarpaulin by means of a mechanical structure with articulated arms. Obviously, this type of structure is heavy and bulky and does not allow a self-driven machine to roll on the tarpaulin without irreparably damaging this metal structure. It is also clear that the complexity of installing such a system only increases with the size of the tarpaulin, the length of the articulated arms being linked to the dimensions of the tarpaulin.